The present invention relates generally to surface maintenance or conditioning machines, and more particularly to those machines employing one or more surface maintenance or conditioning appliances or tools to perform a floor cleaning task.
In general, proper carpet maintenance involves regular vacuuming and periodic cleaning to remove soil by methods such as hot water extraction, shampooing, bonnet cleaning, foam cleaning, etc. Some of the soil is loosely found between carpet fibers while other soil is held upon the carpet fibers by some means such as electrostatic forces, van der Waals forces, or oil bonding. Still other soil is mechanically trapped by carpet fibers. Regular vacuuming is essential as it removes some of the loose soil that damages the fibers. Vacuuming maintains the surface appearance of a carpet and keeps the level of soil in the pile at an acceptable level. Vacuuming removes only particulate soil and some unbound or loosely bound surface dirt; therefore, other methods of cleaning are periodically required to improve the appearance of the carpet. Wet cleaning methods are better for removing oils, greases, bound dirt, and other forms of matter that cause soiling on carpet. These methods are often used by professional cleaners and trained personnel.
One type of surface maintenance machine for carpet cleaning is referred to as a bonnet cleaner. Bonnet cleaners employ an absorbent bonnet or pad (hereinafter referred to as the xe2x80x9cpadxe2x80x9d) attached to a rotary driver for rotating the pad about an axis generally perpendicular to the carpet surface. Cleaning liquid is sprayed directly onto the carpet followed by the rotating pad used to agitate the carpet and transfer soil from the carpet onto the bonnet, i.e., the pad. Since the pad is commonly two-sided, the pad may be reversed once one side of the pad gets soiled to a selected level. The pad may be periodically replaced and later cleaned depending upon the application and wear characteristics of the pad.
The soil transfer process of the bonnet cleaners may be characterized as a xe2x80x9ccircular engagement processxe2x80x9d since the pad rotates relative to the carpet surface. The method employed by bonnet cleaners does have the advantage of being fast drying if a relatively small amount of cleaning liquid is employed. However, limitations of bonnet cleaners include transferring soil from soiled areas to a relatively cleaner area, leaving much of the cleaning fluid in the carpet, and having the potential to damage the carpet. With respect to the latter, some carpets, particular twisted ply variations, may be damaged by aggressive engagement with the rotating pad. Additionally, the bonnet cleaning process is a relatively labor intensive process since the pad requires frequent soil monitoring and frequent removal of soiled pads.
Yet another limitation of bonnet cleaners is the relatively uncontrolled use of cleaning liquid in the carpet cleaning process as some areas of the carpet may receive more cleaning liquid spray than other areas. Reliance on operator spraying of cleaning liquid to the carpet surface may result in overwetting of some areas and underwetting of other areas.
Another type of surface maintenance machine intended for carpet cleaning is referred to as an xe2x80x9cextractor machine.xe2x80x9d Extractor machines are commonly used for deep carpet cleaning. In general, an extractor is a transportable self-contained device which (i) sprays cleaning liquid directly onto the carpet to create a wetted carpet portion, (ii) agitates the wetted portion with a brush, and (iii) removes some of the cleaning liquid and soil in the carpet through a vacuum system. Generally, in the extraction process a relatively large quantity of cleaning liquid is applied on the carpet. While the vacuum system recovers a portion of the applied cleaning liquid, a significant portion is retained by the carpet. As a consequence, carpet drying times are substantially longer than in the bonnet cleaning process. Excessive carpet wetting may promote the growth of fungus and/or bacteria within the carpet. Additionally, carpet overwetting may also cause surface stains to appear or reappear as underlying soil or stains migrate from the bottom of the carpet to its surface. Additionally, extractors are generally limited to a single operational direction as the steps of wetting, agitation, and vacuuming are sequentially performed. As a result, extractor machines may be difficult to maneuver in some environments, i.e., complex floor layouts.
An object of the present invention is the provision of a carpet cleaning machine promoting efficient use of cleaning liquid in carpet cleaning.
Another object of the present invention is to enhance cleaning area per unit of cleaning solution.
Another object of the present invention is to provide a cleaning method that permits a carpet to dry more rapidly.
Yet another object of the present invention is to provide a carpet cleaning process that has the ability to lift carpet pile which exposes more of the carpet fibers to the surrounding drying air so as to permit the carpet to dry more rapidly than if the pile was not lifted.
Yet another object of the present invention is the provision of a cleaning process and apparatus for cleaning a variety of surfaces, including but not limited to floor surfaces, stairways, walls, and upholstered furniture or other fabric surfaces.
The present invention is directed both to a method of cleaning surfaces and an apparatus for performing the method. In a broad sense, the cleaning process is similar to a damp cloth wiping operation wherein soil from a surface is transferred to the damp cloth. More particularly, the cleaning process utilizes:
In accordance with the present invention, a revolving cleaning medium, which after being wiped against a surface intended to be cleaned is wetted, followed immediately by the step of extracting so as to remove cleaning solution and any soil from the cleaning medium, and again wiped against the surfacexe2x80x94the process revolving or repeating. In a preferred operation, one portion of the cleaning medium is wetted with cleaning liquid, while another portion is being extracted to remove soil and cleaning liquid therefrom, and while yet another portion is being wiped against the surface to transfer soil from the surface to the cleaning medium. The process continues in a revolving or cyclical manner so that each portion of the cleaning medium is sequentially wetted, extracted, and wiped against the surface.
The method of cleaning surfaces in accordance with the present invention includes the steps of (i) wetting a revolving cleaning medium with a cleaning solution, (ii) followed by removing at least some of the cleaning liquid from the revolving cleaning medium directly after wetting by way of a moisture extraction device, and (iii) wiping the surface with the revolving cleaning medium so as to transfer soil from the surface to the revolving cleaning medium and subsequently removing transferred soil from the revolving cleaning medium.
In accordance with present invention, a transportable device is utilized to perform the cleaning process on a carpeted surface. The device may be a relatively portable machine having a cleaning liquid tank, a soiled solution recovery tank, a vacuum system, and cleaning head. The cleaning head may include a revolving cleaning medium and associated drive mechanism. A vacuum extractor may be used to engage the cleaning medium to remove soil and at least some of the cleaning liquid from the cleaning medium.
In accordance with one embodiment of the invention the revolving cleaning medium is configured as a pair of counter rotating cylindrical cleaning media having portions of each successively wetted, extracted, and wiped against a surface intended to be cleaned, with the process repeating or revolving.